Oil still



July 3, 1928.

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OIL STILL Filed Febr. 12, 1927 ,S QMS QM WW ATTORNELS Patented July 3, 1928.

UNITED STATES PATENT ori-'ica'.

. EDWARD W. ISOM, F -SCABSDALE, NEW YORK, AND ABNOLDHABLES VOBACH, 0F WHITINGQIN'DIANA, ASSIGNOBS TO SINGLAIB BEFINING COHPAIY, 0l' CHICAGO,

ILLINOIS, A COBPOBATIN 0F MAINE.

OIL STILL.

Application llled February 12, 1927. Serial lo. 167,300.-

This invention relates to improvements in oil stills such as are commonly used in the distillation of hydrocarbon oils` under pressure for the production of lighter. hydrocarbon. oils therefrom. More particularly, this invention relates to improvements in circulatory oil cracking stills in which the main body of oil is maintained fat a cracking V'temperature in a bulk supply tank by circulating the oil from and to thebulk supply tank through a battery of heating tubes ar` ranged in a suitable heating furnace.

In the operation of the apparatus of the invention intimate contact is secured between the oilvbeing treated and the heat transferring surfaces. The length of travel of the circulating oil in contact with the heating surfaces in a still of given dimensions is also increased and the tendency toward local over- .2G heating with the consequent formation of heat insulating carbon deposits' on the heat transferring surfaces greatly reduced, thereby increasing the capacity of the still and the eiliciency ofthe operation.,

The invention is of particular application in connection with oil cracking stills of the general character shown in Patent No. 1,285,200 granted to the Sinclair Refining Company on the application of E. W. Isom,

November 19, 1918.

The cracking of heavier hydrocarbon oils by' distillation under pressure for the productiono lighter hydrocarbon oils therefrom is accompanied by the formation of fixed gas and carbon, pitch, etc., the character and amount of which are functions of the temperature, the amount increasing rapidly as the .temperature necessary to effectthe de-v sired cracking is exceeded. The carbon 40 formed tends to adhere to .the heated surfaces of the still insulating them from the cooling eiect of the circulating oil. This Laction is cumulative and may cause extremely high temperatures to be reached in a comparatively short time which impairs thestrength of the material and sometimes causes rupture of the still or tube walls, but in any event necessitates shutting down the still for cleaning.

According to .the present invention the heating tubes are provided with cores centrally located therein and extending entirely through theheatcd portions thereof. These cores are in the form of twisted rods so as some suitable forcing means such as a pump 50 arranged in the circulating connections. B providing twisted cores in the heating tubes in accordance with the present invention the velocity of circulation is materially increased due to the decrease in cross sectional area of the heating tubes and the correspondingly greater ratio of heating surface to volume. The helical configuration of the cores tends to cause the annular streams of circulating oil surrounding them to assume helical paths of increased length, any centrifugal action Y assisting in preventing the accumulation of carbonaceous material on the heated tube walls and assuring intimate contact of the vcirculating oil therewith. The increased rate of heat transferdue to the greater velocity of flow, and the greater length of travel in contact with theheat transmitting surfaces are both effective in increasing the capacity and eiciency of the operation while thegreater protection against local overheating of, and carbon deposition on, the heated tube walls permits a longer operating time to he obtained between shutdowns for cleaning and repairs.

The invention will be further described in connection with the accompanying drawings illustrating in a vsomewhat conventional and diagrammatic manner one embodiment of the apparatus of the invention, but it is inv90 tended and will be' understood that thev invention is illustrated thereby, but is not limited thereto. v

In the drawings:

l. Fig. 1 is an elevation partly in section of 95 a pressure still embodying the invention;

Fig. 2 is a sectional elevation, to anQenlarge-d scale, of a portion of the battery of heating tubes and the upper header.

The pressure still illustrated in 1 is 10D lill eli

'supported by the beating tubes.

5 il emi i connectin' successives t .e

supply rurn, the circulating lower end of tbe beating tubes. tn

, P end oi tbe beeting tubes end tbe bull; supply drum. The 'vapors eseipmg from tbc bulle supply flru'm to the vapor line 2 may be passed tbrougb tbc reliure tower il in which they may be subjected to direct contact 'uib fresh oil cliergecl to tbe still. The vsp 1 from tbe reiiux tower escape through vapor line 9 to e condenser '10, and receiver 1l from which tbe olistiilel'e end unconcicnse vapors and grises muy be seperately witbn drawn. Helius anni admired il'rcsli oil when fresh oil is introduced into tb# reflux toner., ere returned to tbe still. through connection 12. lilresb oil may be introduced ,to tbe upper end o? the rellux tower through connection 13. Cool fresh oil may be supplied to tbe 'beerings ei' tbe circulating; pump through connection le to cool unil protect the seme. A connection l5 is provided 'for pumping' oui'. und initially cbm-ging tbe still. A. counec tion lli is urrunged Eor withdrawing lier from tbe still ilurinff the operation lli cof The furnace structure compr. s u lirebox l? Wbicb may be oi any usuul or :approved construction furnishing the required e'inoiuii of beet, en uptake 18j :and u, rlownlulic licei.- ing bue lll connecting Witb tbe steek 20. The bettery of oil beeting tubes 3 is suspeurierlverticelly in tbe beating ilus il), ille per bender 21 thereof being:r supported on benino 22 und 213 on top of the fui-nece. The beeted products of combustion dcseeniling tbe beating Hue 19 are ceusecl to circu lute back und. forth over tbe beating tubes byineens oi the bellies :'ll und 25. The .lower end, oi the beating line closed by e perilu tion or iloor 556 arranged somewhat above tbe lower end el the heeting tubes enel supported thereby. The upper enfl of tbe beating flue is elosefl by partition 2'? arranged in tbe opening in tbe top of 'tbe furnace through Wbieb tbe beetin tubes depend, this pertition es well es ige baes 2i end. being The beetu ing tubes 8 of tbe buttery ere thus suspended 'from their upper end' und may expend or contract freely with change of temperature. The battery of beating tubes may likewise be removed es e unit through the openrugz et the top of the furnace for the purpose oi' inspection und repair. The front tubes in the battery of beating tubes ere prevented from receivingI en undue amount ol' heel' by ciircci. radiation from .the rebox 17 by provision of the bridge Weil 28 and tbe elongated flue or uptelre 187 tbe bridge well acting es u screen to cut ofi" direct radiation from the lirebox to tbe beating tubes.

The beating tubes 3 are provided. with twisted. cores 9.9 suitably supported tberein and extending centrally therethrough. @ne

lll El:

particularly adventegeous type of core eonis shown in detail in Fig. 2. lln gement there' shown the cores 29 e from rods of somewhat greater n tbe tubes in which they are nrmi l. oi' some standard .shape such as stsuilurii triangular, square, rectangular or iiexuggon bein. Tile upper ends ol the rods ure bent inform books by which tbe cores nuiy be suspended, but which are of such breadth that they may be readily withdrawn through tbe openings in the headers urrungccl lo register with the ends of the heuting tubes und closed by the removable plugs Si?. l`ln1t portion oi the rods below the suspending books is twisted, tbe edges of the rods forming Y.siicul ridges on their surfeces;

lfiie beating tubes :ire thus provided with" lulicei cores centrally arranged therein and 1 :ruling therethrough which may be readily rcinorcffl to faciliteit-c cleaning, but which ure nevertheless of exceptionally simple und chesp tibougb rugged construction.

in tbe operation of the apparatus of the invention oil is circulated from the bulk supply drum 'l by meuns ci" the circulating pump -l to the lower enel ci' the heating tubes Si und ilieucc upwardly therethrough in relatively iiiin annular streams in intimate .m lect with tbe tube Wells and buck to the bulk supply drum. Circulation is assisted by the progressive beating oi' the oil and the tube wells ere swept clean by the scrubbing action of tbe circulating oil flowing' tbereover. The bot products oi combustion arising from the ir .box are first contacted with the upper end i tbe beating tubes and are then caused to circulate beck and forth over the heating tubes ciowiiwerdly to tbe connection with the steel: Hue 20, tbe loW- of heating gases over the beating tubes being generally countercurrent te tbe low of circulating oil there through.

ln tubular oil cracking pressure stills, a bulli supply drurzn a, battery of beating tubes connected in multiple, end means for circulating beating gases tiiereover, connections between the bulk supply drum and the bet- EDT/YARD W. ESOM. ARNOLD CHARLES VOBACH. 

